Caulking guns of the nature disclosed herein are disclosed in U.S. Pat. No. 4,213,546, which shows such a caulking gun with an improved cap for the cartridge nozzle, and U.S. Pat. No. 4,135,644 which shows such a caulking gun having a cartridge nozzle cutting hole in its handle and also having a cartridge puncturing tool retractably mounted in its handle.